private void Filter_Click(object sender, EventArgs e)
 {
     if (this.RelationItems.CurrentRow.DataBoundItem != null)
     {
         string type = this.RelationType.SelectedItem.ToString();
         if (type == types[0])
         {
             var person = (PersonDTO)this.RelationItems.CurrentRow.DataBoundItem;
             items = service.FilterByRelation(items.ToArray(), person.FirstName, person.LastName, person.Group, type).ToList();
         }
         else if (type == types[1])
         {
             var location = (LocationDTO)this.RelationItems.CurrentRow.DataBoundItem;
             items = service.FilterByRelation(items.ToArray(), location.Name, location.Country, location.Region, type).ToList();
         }
         else
         {
             var property = (PropertyDTO)this.RelationItems.CurrentRow.DataBoundItem;
             items = service.FilterByRelation(items.ToArray(), property.Name, property.Value, string.Empty, type).ToList();
         }
         this.Close();
     }
 }